Instructor actions

Introduce and motivate with the question of how we gauge distance and arrive at the airport without visual references

Describe new navigation systems and their operation in a predominantly lecture format

Illustrate techniques using Tim’s simulator

Review each system before moving on to the next

Evaluate student knowledge with questions emphasizing understanding rather than rote

Have the student solve multiple scenarios

Conclude with an oral quiz, identifying and correcting errors

Student actions

Arrive with completed homework assignment

Maintain active involvement by responding to questions and taking notes

Guide the instructor through the intercepting and tracking of several simulator scenarios

Complete an oral quiz and demonstration of the concepts

Completion Standards

The lesson will be complete when the student can describe DME and ILS equipment – and demonstrate an understanding of the techniques required to smoothly and accurately intercept and track a localizer and glideslope – with minimal instructor guidance.

Teaching outline

Review radio principles

What are the three types of waves?

Which kind of frequency does the ILS use? How about DME?

CDI with localizer and glideslope

Not all CDIs can be used with an ILS, but all should work with a localizer

when flying a localizer, it is four times as sensitive – every dot is .5° rather than 2°

the glideslope needle will be flown just like a normal lateral course – the center is the airplane

performance instrument, used as a reference to adjust control inputs

Instrument Landing System, IF 309 & IFH 7-27

The ILS is a precision approach, providing both lateral and vertical guidance down a predetermined flight path.

As a precision approach, it is designed to transition from instrument to visual flight

Uses a system of ‘lobes’; overlapping points define the approach

VHF band

operates between 108.10 and 111.9 MHz

Five parts make up the ILS in actual use:

localizer provides lateral (directional) guidance

broadcast from the non-arrival end of the runway (illustration from IFH 7-28)

40 channels, on odd tenths between 108.10 and 111.95

the ‘full scale’ of 5° will extend to 700 ft wide at the threshold, varying the localizer width

service volume reaches 18 nm, between 1000 agl and 4500 above the antenna

lateral area is ±10° to 18nm, ±35° to 10 nm, providing proper off-course indications within the volume

glideslope provides vertical guidance with a UHF signal

broadcast from antennas located approximately 1,000 ft from the approach end

40 channels, paired with the localizer

full deflection occurs .7° high or low; useful width is 1.4°

average angle of 3°, but may be as low as 2.5° or as high as 4°

calibrated out to 10 nm from threshold, but reception is common further
false glideslope forms at approximately 12° above the horizontal

this is the danger of intercepting from above

reverse sensing makes it somewhat apparent

intercepts marker beacons at 1400 feet HAT (OM) and 200 feet (MM)

crosses the threshold at approximately 50 feet

marker beacons, IF 324

essentially an extremely low power ADF; designed to create an elliptical ‘fan’ (alternate name: fan marker) that is 2400 feet wide and 4200 feet long at 1000 feet above the antenna